# Proposed AD FAA-2005-22624: Boeing Model 747 Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2006-10-02
- Products: Boeing
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: October 7, 2005, 70 FR 58623
- Comments due: November 21, 2005
- Became: [AD 2006-10-02](https://openairdocs.org/ad/2006-10-02)
- Docket: FAA-2005-22624 (https://www.regulations.gov/docket/FAA-2005-22624, where comments are filed)
- Project: 2004-NM-81-AD
- FR document: 05-20268
- Official PDF: https://openairdocs.org/files/sha256/dc/82/dc82591d79e1cbd5f166de160f5cbd1bca6daf200595eeda22ed1e35e77dcb03 (from https://www.govinfo.gov/content/pkg/FR-2005-10-07/pdf/05-20268.pdf)
- Federal Register: https://www.federalregister.gov/documents/2005/10/07/05-20268/airworthiness-directives-boeing-model-747-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1B723629F10CE0068625709300551D8E.0001
- Page: https://openairdocs.org/proposed/FAA-2005-22624

## Summary

The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 747 airplanes. This proposed AD would require the following actions for the drive mechanism of the horizontal stabilizer: Repetitive detailed inspections for discrepancies and loose ball bearings; repetitive lubrication of the ballnut and ballscrew; repetitive measurements of the freeplay between the ballnut and the ballscrew; and corrective action if necessary. This proposed AD is prompted by a report of extensive corrosion of a ballscrew in the drive mechanism of the horizontal stabilizer on a similar airplane model. We are proposing this AD to prevent an undetected failure of the primary load path for the ballscrew in the horizontal stabilizer and subsequent wear and failure of the secondary load path, which could lead to loss of control of the horizontal stabilizer and consequent loss of control of the airplane.

## Notices in this docket

- Oct 7, 2005: Notice of proposed rulemaking (NPRM). (first notice), FR document 05-20268, comments due Nov 21, 2005 (https://www.federalregister.gov/documents/2005/10/07/05-20268/airworthiness-directives-boeing-model-747-airplanes)

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